"I suspect that when the dust settles the transaction will be cleared, but I wouldn't be surprised if there were strings attached," said Jeffrey Silva, a telecom policy analyst at Medley Global Advisors.
The Federal Trade Commission is investigating Google businesses such as search and advertising to determine if the company is abusing its market dominance to squelch competitors.
The acquisition of Motorola, however, is likely to be reviewed by the Justice Department, which normally handles telecommunications deals.
In April, justice officials approved Google's purchase of travel data company ITA Software Inc. But the approval came with conditions, including a requirement that Google license ITA's software to other websites on reasonable terms.
Google would pay $40 a share for Motorola Mobility — a 63% premium over the company's closing stock price Friday. On Monday, investors bid up the price of Motorola's stock 55%, to $38.12. Google shares dipped nearly 1.2%, to $557.23.